1. Field of the Invention
The present invention generally relates to photon detection and, more particularly, to the calibration of a photon detector by electron-photon coincidence.
2. Description of the Prior Art
The need for the calibration of photon detectors of unknown efficiencies is well known. Various instruments and techniques have been developed for the calibration of such detectors in the various regions of the spectrum, such as the visible, ultraviolet (UV) and vacuum ultra-violet (VUV) regions. Many of these instruments are quite complex and very expensive. Also, they are not useful at very low light levels. For example, the instrumentation which employs the synchrotron radiation technique and which can be used below 1000 .ANG. is very expensive and complex. Also, since therein the radiation intensity is very high, it cannot be used for low light level measurements.
A need therefore exists for a new arrangement for calibrating a photon detector for low light level measurements, particularly in the UV and VUV regions.